Neuroprotective electrical stimulation

Abstract

Apparatus is provided that includes one or more electrodes, configured to be applied to a sphenopalatine ganglion (SPG), a greater palatine nerve, a lesser palatine nerve, a sphenopalatine nerve, a communicating branch between a maxillary nerve and an SPG, an otic ganglion, an afferent fiber going into the otic ganglion, an efferent fiber going out of the otic ganglion, an infraorbital nerve, a vidian nerve, a greater superficial petrosal nerve, or a lesser deep petrosal nerve; and a control unit, configured to drive the electrodes to apply electrical stimulation to the site, and configure the stimulation to excite nervous tissue of the site at a strength sufficient to induce at least one neuroprotective occurrence selected from the group consisting of: an increase in cerebral blood flow (CBF), and a release of one or more neuroprotective substances, and insufficient to induce a significant increase in permeability of a blood-brain barrier (BBB).

The invention claimed is: 
     
       1. Apparatus for treating a subject, comprising:
 one or more electrodes, configured to be applied to a site of the subject selected from the group consisting of: a sphenopalatine ganglion (SPG), a greater palatine nerve, a lesser palatine nerve, a sphenopalatine nerve, a communicating branch between a maxillary nerve and an SPG, an otic ganglion, an afferent fiber going into the otic ganglion, an efferent fiber going out of the otic ganglion, an infraorbital nerve, a vidian nerve, a greater superficial petrosal nerve, and a lesser deep petrosal nerve; and 
 a control unit, configured to: 
 drive the one or more electrodes to apply electrical stimulation to the site, and 
 configure the stimulation to excite nervous tissue of the site at a strength that (a) is sufficient to induce at least one neuroprotective occurrence selected from the group consisting of: an increase in cerebral blood flow (CBF) of the subject, and a release of one or more neuroprotective substances, and (b) is insufficient to induce a significant increase in permeability of a blood-brain barrier (BBB) of the subject. 
 
     
     
       2. The apparatus according to  claim 1 , wherein the control unit is configured to set the strength to less than 90% of a strength sufficient to induce the significant increase in the permeability of the BBB. 
     
     
       3. The apparatus according to  claim 1 , wherein the control unit is configured to set the strength to less than 40% of a strength sufficient to induce the significant increase in the permeability of the BBB. 
     
     
       4. The apparatus according to  claim 1 , wherein the control unit is configured to set the strength to more than 50% of a strength sufficient to induce the significant increase in the permeability of the BBB. 
     
     
       5. The apparatus according to  claim 1 , wherein the site includes the SPG, and wherein the electrodes are configured to be applied to the SPG. 
     
     
       6. The apparatus according to  claim 5 , comprising an elongated support element configured to be placed within a greater palatine canal of the subject, sized to extend from a palate of the subject to the SPG, and having a distal end, wherein the electrodes are fixed to the support element in a vicinity of the distal end thereof. 
     
     
       7. The apparatus according to  claim 1 , wherein the control unit is configured to configure the stimulation to induce the at least one neuroprotective occurrence without producing a measurably-harmful clinical effect for the subject.